Control system for electric motors.



A. .l. HALL & L. G. RILEY.

CONTROL SYSTEM FOR ELECTRIC MOTORS.

APPLICATION FILED JULY 9. 1913.

1,143,956. Patented June 22, 1915.

2.5HEETS-SHEET I.

a WITNESSES.- s 2:: Pat: 5 EN RS d fi E 1 m ATTORNEY A.J.HALL & L G.R|LEY.

CONTROL SYSTEM FOR ELECTRIC MOTORS.

APPLICATION FILED JULY 9, I913. 1,143,956. Patented June 22, 1915.

2 SHEETS-SHEET 2.

ATTORNEY 'uivimunsTAmEs ram omen man a a. HALL'AND LYNN er. RILEY, or wuxmsntme, rnmwsnvnrm, as To wnsmmenousn ELECTRIC AND manurac'runme comm; .aconro Oil? PENNSYLVANIA.

IGNOBS :ATION Specifistibn of Letters recent.

To an whom; it may concern.

Be it known that we, ARTHUR J. HALL,-a subject 'of the King: of -Great Britain, and LYNN G.- RILEY, a citizen of the United states 'and resident's ofi Wilkinsburg, in the county of Allegheny and State of Pennsylvania; have-invented a new and useful Improv'ement-in Control Systems for Electric Motors, ofwhich-ithe following is *a specification.-

Our'inventionhrelates to control systems foeelectric-motors, and it has special ref erenceto systems adapted' to control the operation of the motors of -an-' electric locomotive or motor carope'rated upon -asingle phase'alternating current railway system.-

Oneof the objects of'our invention is to provide a systemofthe above indicated character which shall be simple in arrangement'i easy tomanipulate, and particularly adapted for theautomatic control of aplurality of motorsduringwtheperiod'ofaccelerationi Another objectofour invention is to provide acontrol-system for single phase motors which shall be adapted-ffor a plurality of economical running. positions in which the energy is directly suppliedto themotors andis I not consumed by resistors or other energy-consuming devices.-

Astill further object of our invention is to-provideautomatic means which shall be dependent upon predetermined circuit conditions for progressively'connecting the-motors through a plurality ofresistors to a plurality of taps provided in an auto-transformer which is-normally in circuit between the source-o5 energy and the return circuit,

N still-iurther objectof ourinvention is to *provide a -contro'lsystem govemmg the operation of" single-phase alternating current motors, embodying a plurality of electrically operated or electrically controlledmain switches which are provided with interlock switches and having, the train line wiresand' the energizing coils of the main switches connected through the master controllerto the positive side of'a control battery or similar'source of energy, and the interlock switches and -the liniitswitch -t0 the negative-sidethereof; in order to assure a positive progression of -theswitches and to prevent an accidentall progres'sionthereof andconsequent-acceleration-of the motors in case of'abreak in anytof the train line wine s.

Patented Jimezz, 1915;

Astill'ifurther object of'our invention is p to provide-an inc): ensive control system which shall beeasily installed and= maintained at a low' cost and which,- by reason of its automatic features, shall prevent abuse ofthe motors-by subjecting; them to an abnormal rate of acceleration.-

Inthe prior art, it has been customary to employ, control systems for single phase motors which-embody auto-transformers having. a plurality of'taps and a plurality of so-cal1ed preventive coils through which the energy is supplied to the motors. Such anarrangementof circuits, however, necessitates an excessive number of switches which complicates the system; increases its cost and reduces its reliability and eflectiveness: Another'type of control which has been employed, utilizes a-plurality of resistors in place' ofthe preventive coils referred to, which-results in: fewer switches and better operation. However, this class of-systems has never been adapted for automatic operation, nor for a positive progression-of the several switches,-

It'is our purpose to-provide a system of control which shall overcome the diificulties of theprior art' and shall obtain the objects I and results heretofore mentioned.

Our-invention may best be understoodreference to the accompanying -drawings, in which i Figure 1 is a diagrammatic view showswitches with which they are associated.

By so doing, the diagram of connections is greatly simplified and the operation and' circult connections will be more easily understood. Fig. 3 is'a chart showing-.the positions of the various switches which correspond to the different running positions or steps of the master controller. Charts of this type are well known in the art and will be readily understood.

In order to set forth our invention with clearness, we shall first describe the main circuit connections shown in Fig. 1 and the general operation of the system, and then willdiscuss the control circuits and the operation thereof.

Reference may now be had to Fig. 1 in which the system shown comprises a supply circuit conductor marked rolle ,'a re turn circuit conductor marked rack,fa plurality. of motors having armatures M and M andfield win F and F, a transforming device mar ed Autotransformer which is adapted to be connected between the trolley and the track" and is provided with a plurality of intermediate taps 10 -11 and 12 a plurali of resistors R1 a Ba ty severally connected between the taps 10, 11 and 12, a plurality of electrically operated switches mpairs in series circuit with the several taps 10, 11 and 12, the switches of each pair being connected on opposite sides of the point at which the'resistors R, R and R are connected,these several switches being adapted to govern the circuit connections for the resistors R Bkand R, a. motor circuit switch #7 connected between the -motors M and M and the taps 10, 11 and 12, a switching device marked Reverser for adjusting the connections of the field windings F and F, a limit switch one of the motors for governing the automatic operation of the system in accordance with predetermined circuit conditions, a relay marked Line relay forjnterrupting the operation of the'system in case of a novoltage condition, a main switch marked Line switch connected between the troll ey and the 5 auto-transformer and serving as a circuit breaker, and a relay device marked Overload trip for vernin the operation of the line switch in accor an with current conditione 4 V I All of the apparatus referred to, with exception of the overload trip, is of "own construction and those skilled in the art-are familiar with their operation,

fore, no description of either their construction or operation will be given. It should be noted, however, that, although the several switches illustrated as operated directly by magnets, we prefer toe'mploy pneii operated switches, in whiclrcase, electro-magnets illustrated will used to control the operation of suitable valves associated with aircylinderslof any well-known type. The switches #1 to #7,-

#5 and #6 which are connebted z connected in series with #1 to #7, inclusive, have been Th inclusive, are ada ted to occup two positions, one in whic the switch is open and termed the switch-out position and the circuit between the trolley and the autot transformer and is traversed by the full current of the motors. Under abnormal conditions, the overload trip is energized and raised in the usual manner and is retained in its raised position by an auxiliary device until energy is supplied to its reset coil and permits it to fall into its normal operative position.

'ng that the several devices occupy the positions shown in Fig. 1, the acceleration of the motors in a forward direction may be accomplished by first closin the line switch, motor circuit switch I and the resistor switch #1, thus completinga circuit from'the trolley through switch 15, the energizing coil of the overload trip, the hne switch, a portion of the windings of the auto-transformer, conductor 10, switch #1, resistor R, conductor 16, switch #7, and thence, in a divided multiple circuit, through the armatures M and M and field windings F and F of the several motors, as well as the reverser, limit switch being included in circuit with the armature M and field winding F. Under these conditions, energy is su plied to the motors from tap 10 of the autotransformer through the resistor R and the motors are thus started into operation, as will be readily understood. Switch #2 1s then closed, thus short circuiting the resistor R and connecting the motors directly to the to the return circuit track, the

auto-transformer, these connections corresiponding to the first running position.

* 11 order to' increase the motor speed, switch #3 .is closed, thus stepping up the motor connections to tap 11 and mserting in circuit therewith. Immediately upon e closure of switch #3; is c d to p thus, temporary local closed autof transformer throu Followiikgthe closure of the switch #3, the

f ais excluded from circuit by closswiteh?#4, thus connecting the motors directlyto'tap 11 of the auto-transformer.

ese' constitute the arrangement of for of motor Speed the autoby e ecting the closure of As insuring onlir iicircuit upon h resistor R.

the geeond running poeally' sition. m y be an Qtransformer-ctmnection to 7 tap 12 and in resistor R in circuit with themetors Switch #6 is then closed to shortci-rcuit resistor= Rand connect the motors directly to tap12, in which case, substantially full operating voltage is impressed upon the .motors and consequently full-speed conditions are obtained.

It will be understood that as the connections of the motors are pro ressively changed to taps 10,41 and 12 oft e autotransformer, the voltage impressed upon the motors is increased in steps. Furthermore, an intermediate step between each two successive-running positions is effected'b means of the resistors R, R and R, eac ofwhich issuccessively included in circuit and excluded therefrom to prevent a local short circuit of the auto-transformer.

Having described the general operation of the system, the arrangement of circuitsof the control system and the operation thereof will beset forth.

Referring-now particularly to Fig. 2, the control circuits shown are adapted to be arranged and governed by means .of a handoperated switching :device :marked Master controller which comprises a rotatable drum (not shown) having a plurality of conducting segments 20, 21 and 22, a development of which is shown in the figure. The several conducting segments just referred to,

are electrically connected and are adapted to cooperate with a, plurality of contact terminals 1, 2, AB+, 3, 4 and 5 whichareidivided into two groups that are respectively disposed intermediate'the conducting segments 20 and 21, and-21 and 22when the controller occupies its 05 position. The master controller is adapted for movement in opposite directions, one of which arranges the circuit connections for forward rotation of the: motors and the other for reverse operation. Three-forward running positions are provided, in which the'condueting-segments engage the cooperating contact terminals along the position-indicating lines 1, 2 and 3 marked For,-and;a like-number of reverse positions 1,2 and 3 and-marked Rev.

Associated with the master controller are a plurality of sockets marked Reset socket and Line switch'socket which are adapted to receive a conducting plug (not shown) for making electrical connection be;

tween theseveral conductinges'egments 24- hereinafter thereof, for a purpose to pointed out. I

As already mentioned, the control system is adapted to arrange the circuits for three running positions or for full automatic'ao celeration in which the circuit conhections are governed to effect a smooth accelerationv of the motors from rest up to full-speed operation. Provision is made to secure automatic acceleration for any position of the master controller.

Assuming the apparatus and/connections to be as shown in the diagram, the acceleration of the motors in a-forward direction through the several running positions is secured as follows:The motorman or operator first inserts a suitable contact plug (not shown) into the receptacle marked Line switch socket, thereby establishing electrical connections between the several conducting segments 24 thereof and completing a circuit from the positive side of the battery through the battery switch, conductor and train line B+, line switch socket and plug (not shown), conductdr and train line 8, overload trip, line switch coil conductor B, and the battery switch to the negative side ofthe battery. Thus the energizing coil of the line switch effects the closure thereof and supplies energy from the trolley to the auto-transformer, as hereinbefore described. Concurrently with this operation, a circuit is established from the line switch socket throu h conductor AB-i-yto contact terminal B, and, if the master con troller is then moved into position for 1, the circuit is completed through conductingsegments 21 and 20, contact terminal 1, conductor and train line 1, conducting segment-25 of the reverser conductor R, energizing coil of'switch #7, conductor B- and the battery switch to the battery. Switch #7 is thereby closed, which causes the closure of its interlock switch #7--in.

-At the same time, a circuit is established from the conducting segment 21 of the master-controller through contact terminal 3,

conductor and train line 3, energizing coil of switch #l,-conductor 26,) interlock switch #3-out, conductor 27, interlock switch #4out, conductor 28, interlock switch closure -of .switch #7 is eifected, thereby completing a main motor circuit from tap 10 of the auto-transformer through switch #51, resistor R conductcr 16, and switch 7- to the driving motors. The motors are t en started'from rest in a forward direction and, as soon as the current traversing them decreases to a value for which the limit switch is adjusted, it is allowed to fall and bridge itsstationary' contact members, thereby completing a control circuit from'conductor R- throu h the energizing coil of switch #2, interloc switch #2-out, conductor 30, interlock switch I 1-in, conductor 31, limit switch andt ence to the negative side of the battery through a circuit already traced. Thus switch #2 is closed in accordance with the actionof the limit switch, thereby excluding resistor, R from the main motor circuit and estabtor 31 and thence through the Limit switch to the battery through a circuit already traced. Switch #3 is thus closed to deliver energy from tap 11 of the autotransformer through resistor R and switches #2 and #7 to the driving motors. As soon as switch #3 closes, it transfers the connection of its energizing coil to a holding circuit 28, through interlock switch #3in, and, at the same time, interrupts the energizin circuit of switch #1 at interlock switc #3out. Thus, switch #1 isimmediately allowed to open to break a local closed circuit across a section of the autotransformer i Following the opening of switch #1 and,

' to short circuit m accordance with the action of the limit switch, switch 34 is energized and closed e'resistor R'and connect the motors to the tap 11 of the auto-transformer in the second position.

By reason of the ease with which. those.

skilled in the art may trace the control circuits, and may understand the operation of the system inview of the detailed description thereof that has already been given, it isnot deemedn totrace the remaining circuits in detail, ut only to recite, in a general way, the further operation of the sistem. The circuits and the 0 tion will 0 viousl be similar to those ereinbefore In order to secure a higher of the motors, the master controller is moved into its tion For 3, thereby energizing the train line and conductor 5 and the energizing coil of switch #5 through a circuit including interlock sw1tches'#5in, #4-in, #2in, and #1out. As switch #5 closes, it transfers its connection to a holding circuit 29 and also interrupts the energizi circuit of switch #3. The closure 2% switch #5 connects the motors through resistor R to tap 12 of the autotransformer. As soon as the switch rmits, switch #6 is energized' m conl ictor 5 through several interlock switches andis thus closed to exclude resistor R and connect the driving motors directly to tap 12 of the auto-transformer, whereby the highest operating voltage is rmed upon the enotors and full-speed conditions are attain 1,14a,eoe

may be secured by moving the master controller initially into its third r nning position. In this case, the several itches are automatically controlled in accordance with predetermined current conditions and in a predetermined sequence, to bring the motors gradually and uniformly up to full-speed running conditions. Anyintermediate running position may be secured by moving the master controller to the position corresponding to the operating conditions desired.

One of the advantageous features of the system of our invention is that the master controller and train'lines are connected to the positive side of the battery, or other source of energy,'while the interlock switches and the limlt switch are connected to the negative side thereof. Thus, the operation is positive and reliable, and unexpected acceleration ofthe motors cannot be caused by an accidental break in any of the train lines, as has been possible in systems of this type heretofore.

In the event of a. no-voltage condition obtaining upon the system, the line relay is immediately dropped to interrupt the en; ergizing circuits of the switches #1 to #6, inclusive, thereby making it necessary to start the operation again from the initial position.

In case an abnormal current traverses the circuit, the'overload trip is raised and thus deiinergizes the line switch and causes it to open the main circuit. By reason of the accessories with which the overload trip is provided, it is maintained in its raised inoperative position until the plug (not shown) is removed from the line switch socket and inserted into the reset socket to establish a circuit from the reset socket through the conductor and train line 7, interlock switch #7-out, overload trip and reset coil to conductor B. Upon energization of the reset coil the overload trip is allowed to drop into its initial position to bridge its contact terminals and incomplete a circuit through. the energizing coil of the f line switch. In order to close the line switch, it is then necessary to insert the plug (not' shown) into the receptacle line g switch socket after which the operation of the system is similar to that hereinbefore described.

Reverse operation of the driving motors may be secured, either step-by-step or automatically, by moving, the master controller into any of its positions Rev. 1,

2 and 3. No description of this operation Wlll given asjt issimilar to that already described and will, readily be understood by We, have shown our invention and der thoseskilledintheart, Iii-view of the description of the operation scribed itszoperation. as applied to the con-h trol-of railway motors but .itjs in no sense restricted. to; such service and may be employed ineonnectionwith the control of any electrically propelled. vehicle orthe. like. Our invention is setv forth in, whatrwe now consider. to. be, its preferredfiembodiment but, it ;is.our' intention. to cover by the. appended. claims. all -modifications therein which. do not depart from the spirit and scopeoi our invention.

We @claim. as our invention 1. In a. control system, the combination with a source of energy,- an electric. motor adapted to be connected thereto, and a plurality of resistors adapted to be successively connected to said source and in series with said motor, of a plurality of switching de- Vices for efi'ecting said connections, and means for causing an automatic operation of said swltchlng devices durmg the accelerating period of said motor.

2. In a control system, the combination with a source of energy, an electric motor adapted to be connected thereto, and a plurality of resistors adapted to-be successively connected to said source and in series with said motor, of electro-responsive means' for automatically effecting the connections of said motor and said resistors during the period of accelerating said'motor. v

3; In a control system, the combination with a source of energy, an electric motor adapted to be connected thereto, a plurality .of resistors adapted to be succe$ively connected to said source and in series with said motorfand a plurality of independently operated switches for effecting'said connections, of automatic means dependent upon the current traversing said motor for governing' the progressive closure of said switches and effecting a smooth acceleration of said I motor.

4. In a control system, the combination with a source of energy, an electric motor adapted to be connected thereto, and a plurality of resistors adapted to be successively connected to said source and in series with said-motor, of a plurality of electro-magnetically operated switches for arranging the connections of said motor and said resistors, and automatic means for governing the operation thereof in accordance with predetermined circuit conditions.

5. In a control system, the combination with a source of energy, an electric motor adapted to be connected thereto, and a plurality of resistors adapted to be successively connected to said source and in series with said motor, of a plurality of electro-magnetically operated switches for arranging the connections of said motor and said re- 1 electromagnetically. operated switches, in 1 acswitching devices to eflect said connections.

7. In a control system, the combination with a derived source oi energy havinga plurality of intermediate: taps, an electri c motor adapted. to be successively connected in circuit with said taps, and a plurality-of resistors respectively connected between said taps, of automaticmeans for effecting the connections ofrs'aid motor inapredeten' mined sequence.

8. In a control system, the combination I with an-autoetransformer having a plurality; of taps, a plurality of resistors severally connected between said taps, and a plurality of electrically operated switches connected in each tap in pairs, one on each side of the associated resistors, of an electric motor, and automatic means for governing the operation of said switches to cause said motor to be connected successively to said taps through the respective resistors during the acceleration of said motor;

9. In a control system, the combination with a source of energy divided into sections and having intermediate taps, a plurality of resistors and an electric motor, of independently operated switches for successively connecting said resistors temporarily in multiple to said respective sections and in series with said motor, and then to said taps and in series with said motor, and means for governing the progressive operation of said switches in accordance with circuit conditions. v

10. In a control system, the combination with a source ofenergy having a plurality of taps and intermediate sections, an electric motor adapted to be successively connected to said taps, and independently operated switches for effecting the connections of I said motor to said taps, of a plurality of resistors adapted to be successively connected between adjacent taps in multiple to said intermediate sections of said source of energy and in series with said motor, and automatic means for governing the operation of said switches in accordance with current conditions.

11. In a control system, the combination with a source of energy divided into sections and having intermediatetaps, a plurality of sections of resistance and anelectric motor,

12. In acontrol system, the combination with a source of ener divided into sections and havin intermediate taps, a plurality of sections 0 resistance and an electric motor,

of a plurality of independently operated switches between the intermediate points of said resistance sections and the motor and between said points and the respective taps, and automatic means for governing the closure of said switches in a predetermined sequence to connect said motor successively to said taps and in series with said resistor sections without interrupting the motor circuit and short-circuiting any section of the source of energy.

13. In a controlsystem, the combination with a source of ener divided into sections and having intermediate taps, a plurality of resistors respectively adapted to be connected in multiple to the respective sections of said source, and an electric motorada'pted to receive energy from said source, of a plurality of independently operated switches for successively connecting said motor to said intermediatetaps and in 'seriescircuit with the respective resistors and for connecting each resistor in multiple to its corresponding section of said source in stepping up from one tap to another, and means for rendering the dprogressive closure of' said switches depen ent upon the motor current.

In testimony whereof, we have .hereunto subscribed our names this 27th day of June,

' ARTHUR J. HALL.

LYNN G. RILEY.

Witnesses:

' B. B. Hnms,

LOEL F. LIVERMOKE. 

